With development of wireless communications technologies, a wireless communications system imposes a higher requirement for antenna performance. An array antenna system can implement spatial electronic scanning of an antenna beam, and therefore is more widely applied to the wireless communications system.
The array antenna system is an antenna system including multiple antenna units arranged according to a rule. A phased array system is an array antenna system that can adjust phases and/or amplitudes of antenna units. Phases and/or amplitudes of signals inputted to the antenna units of the phased array system may be adjusted, so as to change a spatial direction of an antenna beam. In this way, automatic beam tracking upon antenna shaking and automatic alignment of an antenna beam can be implemented by using the phased array system with reference to a control algorithm. Therefore, a deployment time and cost can be greatly reduced by using the phased array system as an antenna of a communications device. In addition, the phased array system can be installed in a location with a poor stability condition such as a street pole due to advantages such as windproof and shakeproof.
In a conventional phased array system, each antenna unit is an independent channel. To implement two-dimensional beam scanning in a horizontal direction and a vertical direction, a corresponding radio frequency channel needs to be configured for each antenna unit. Each radio frequency channel generally includes a phase shifter and/or a variable gain amplifier. Generally, there is an interval of a half wavelength between antenna units to avoid generating a grating lobe. For an array system with m×n antenna units, m×n radio frequency channels are required. However, a relatively large quantity of radio frequency channels causes a complex phased array system, and consequently, power consumption and costs are higher.
By using an antenna unit with an increased gain, a quantity of radio frequency channels and a quantity of phase shifters can be reduced, and therefore complexity of the phased array system can be reduced. However, the antenna unit with the increased gain causes an increased interval. Consequently, a grating lobe occurs in the phased array system, and an application requirement cannot be met.